Projection optical apparatus, exposure method and apparatus, photomask, and device and photomask manufacturing method

ABSTRACT

When forming a magnified image of a mask pattern on an object with a plurality of projection optical systems, projected images of the projection optical systems are formed to be accurately continuous to enable satisfactory pattern transfer. A first projection optical system directs light beam from point a on a mask to point A on a plate and forms a magnified image of the mask on the plate. A second projection optical system directs light beam from point b on the mask to point on the plate and forms a magnified image of the mask on the plate. A first line segment linking point A and point a′, which orthogonally projects point a on the plate, and a second line segment linking point B and point b′, which orthogonally projects point b on the plate PT, overlap each other as viewed in a non-scanning direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priorities fromU.S. Provisional Application No. 60/878,383 filed on Jan. 4, 2007, theentire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a projection optical apparatus forforming a magnified image of a first object such as a mask onto a secondobject such as a photosensitive substrate, and to an exposure techniqueand a device manufacturing technique using such a projection opticalapparatus. The present invention further relates to a photomask on whicha pattern transferred by the projection optical apparatus is formed andto a method for manufacturing such a photomask.

A projection exposure apparatus, which projects a pattern of a mask(e.g., reticle or photomask) onto a resist-coated plate (e.g., glassplate or semiconductor wafer) using a projection optical system, is usedwhen manufacturing devices such as semiconductor devices and liquidcrystal display devices. A projection exposure apparatus employing astep-and-scan method (stepper) has been widely used in the prior art.The step-and-scan projection exposure apparatus performs batch exposureof mask patterns onto a plurality of shot-regions defined on a plate. Astep-and-scan scanning projection exposure apparatus, which uses aplurality of small partial projection optical systems having the samemagnification, instead of a single large projection optical system hasbeen proposed recently. In the scanning projection exposure apparatus,the plurality of partial projection optical systems are arranged atpredetermined intervals in a number of rows along a scanning direction.The scanning projection exposure apparatus exposes patterns of a maskusing the partial projection optical systems onto a plate while scanningthe mask and the plate.

Each partial projection optical system of the conventional scanningprojection exposure apparatus includes a catadioptric system, whichforms an intermediate image using for example a concave mirror (orsimply a mirror) and a lens, and further includes another catadioptricsystem. Each partial projection optical system forms an erect image of apattern of the mask onto the plate with the same magnification.

In recent years, the plates that are used have become large and may havea size of as large as 2×2 meters are increasingly used. When theabove-described step-and-scan exposure apparatus, which includes thepartial projection optical systems having the same magnification, isused to perform exposure on such a large plate, the mask is alsoenlarged. A larger mask results in higher costs due to the need tomaintain flatness of the mask substrate and the more complicatedmanufacturing process that becomes necessary when the mask is enlarged.Further, masks in four to five layers are usually necessary to form, forexample, a thin-film transistor portion of a liquid crystal displaydevice. This further increases costs. Accordingly, a scanning projectionexposure apparatus that can reduce the size of a mask pattern has beenproposed (refer, for example, to U.S. Pat. No. 6,512,573). The scanningprojection exposure apparatus uses a multiple lens system that includesa plurality of partial projection optical systems having magnificationsenabling enlargement instead of equal magnifications. In this scanningprojection exposure apparatus, the partial projection optical systemsare arranged in two rows in the scanning direction.

However, each partial projection optical system of the conventionalenlargement magnification multiple-lens system has an optical axis onthe mask and an optical axis on the plate arranged at substantially thesame positions. Thus, a pattern exposed onto the plate by a partialprojection optical system in one row and a pattern exposed onto theplate by a partial projection optical system in the other row are notcontinuous with one another.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide aprojection technique and an exposure technique for enabling optimumpattern transfer when a magnified image of a mask pattern is formed onan object, such as a plate, using a plurality of projection opticalsystems (partial projection optical systems), and a device manufacturingtechnique using the exposure technique.

It is another object of the present invention to provide a photomask foruse in the projection technique and the exposure technique and atechnique for manufacturing the photomask.

A first aspect of the present invention is a projection opticalapparatus for forming a magnified image of a first object on a secondobject. The first object is arranged in a first plane, and the secondobject is arranged in a second plane relatively movable to the magnifiedimage in a predetermined first direction. A first view point and asecond view point are set in the first plane, and a first conjugatepoint and a second conjugate point respectively corresponding to thefirst view point and the second view point are set in the second plane.The apparatus includes a first projection optical system for directinglight beam from the first view point to the first conjugate point andforming a magnified image of the first object in the first plane on thesecond object in the second plane. A second projection optical systemdirects light beam from the second view point to the second conjugatepoint and forms a magnified image of the first object in the first planeon the second object in the second plane. The first projection opticalsystem includes a first light beam transfer member for transferring thelight beam from the first view point to the first conjugate point byshifting the light beam in the first direction from the first viewpoint. The second projection optical system includes a second light beamtransfer member for transferring the light beam from the second viewpoint to the second conjugate point by shifting the light beam in thefirst direction from the second view point.

A second aspect of the present invention is a projection opticalapparatus for forming a magnified image of a first object on a secondobject. The first object is arranged in a first plane, and the secondobject is arranged in a second plane spaced from the first planerelatively movable to the magnified image in a predetermined firstdirection. The apparatus includes a first-row projection optical systemincluding a plurality of projection optical systems, each having aviewing field on a first row extending along a second direction thatintersects the scanning direction. A second-row projection opticalsystem includes a plurality of projection optical systems, each having aviewing field on a second row extending along the second direction anddiffering from the first row. The first-row projection optical systemforms, on the second plane, a plurality of image fields conjugate to theplurality of viewing fields of the first-row projection optical systemalong a third row. The second-row projection optical system forms, onthe second plane, a plurality of image fields conjugate to the pluralityof viewing fields of the second-row projection optical system along afourth row. The first row is between the second row and the fourth rowand the second row is between the first row and the third row when thefirst to fourth rows are viewed in a direction linking the first planeand the second plane.

A third aspect of the present invention is a projection exposureapparatus for exposing a second object with illumination light via afirst object. The apparatus includes an illumination optical system forilluminating the first object with the illumination light. A projectionoptical apparatus according to the above aspect forms an image of thefirst object illuminated by the illumination optical system on thesecond object. A stage mechanism relatively moves the first object andthe second object in the first direction using enlargement magnificationof the projection optical apparatus as a velocity ratio.

A fourth aspect of the present invention is a projection exposureapparatus for exposing a first object arranged in a first plane and asecond object arranged in a second plane while relatively moving thefirst object and the second object in a predetermined scanningdirection. The first plane includes a first viewing field and a secondviewing field, and the second plane includes a first projection fieldand a second projection field. The apparatus includes a first projectionoptical system for projecting a magnified image of part of the firstobject in the first viewing field onto the first projection field of thesecond plane. A second projection optical system projects a furthermagnified image of part of the first object in the second viewing fieldonto the second projection field of the second plane. A stage mechanismrelatively moves the first object and the second object in the scanningdirection using enlargement magnification related with the scanningdirection as a velocity ratio. The enlargement magnification of thefirst projection optical system and the second projection optical systemrelated with the scanning direction is less than −1.

A fifth aspect of the present invention is an exposure method forexposing a second object with illumination light via a first object. Themethod includes illuminating the first object with the illuminationlight, projecting an image of the illuminated first object onto thesecond object with a projection optical apparatus according to the aboveaspect, and relatively moving the first object and the second objectusing the enlargement magnification of the projection optical apparatusas a velocity ratio.

A sixth aspect of the present invention is a device manufacturing methodincluding an exposure step of exposing a mask pattern onto aphotosensitive substrate using a projection exposure apparatus accordingto the above aspect and a development step of developing thephotosensitive substrate that has been exposed in the exposure step.

A seventh aspect of the present invention is a photomask fortransferring a pattern onto a predetermined substrate. The photomaskincludes a first-row pattern part and a second-row pattern part spacedfrom each other in a first direction on the photomask. The first-rowpattern part includes a first inverted pattern obtained by inverting apattern in a first original pattern field, which is part of an originalpattern corresponding to the pattern transferred onto the predeterminedsubstrate, using the first direction as an axis of symmetry. Thesecond-row pattern part includes a second inverted pattern obtained byinverting a pattern in a second original pattern field, which differsfrom the first original pattern field, using the first direction as anaxis of symmetry. The first-row pattern part and the second-row patternpart include a common inverted pattern obtained by inverting an originalpattern in a common field between the first original pattern field andthe second original pattern field using the first direction as an axisof symmetry.

An eighth aspect of the present invention is a method for manufacturinga photomask according to the above aspect. The method includes preparingthe original pattern, extracting first pattern data, which is data ofthe original pattern in the first original pattern field that is part ofthe original pattern, second pattern data, which is data of the originalpattern in the second original pattern field that differs from the firstoriginal pattern field, and common pattern data, which is data of theoriginal pattern in a common pattern field between the first and secondpattern fields, inverting the first pattern data, the second patterndata, and the common pattern data using the first direction as an axisof symmetry to obtain first inverted pattern data, second invertedpattern data, and common inverted pattern data, and writing the firstinverted pattern data and the common inverted pattern data to a firstfield on the photomask and writing the second inverted pattern data andthe common inverted pattern data to a second field on the photomask toform the first-row pattern part and the second-row pattern part.

A ninth aspect of the present invention is a photomask for transferringa pattern onto a predetermined substrate with first and secondprojection optical systems having a predetermined projection magnitude.The photomask includes a first pattern part and a second pattern partspaced from each other in a first direction on the photomask. A firsttransfer field in which the first pattern part is transferred onto thesubstrate by the first projection optical system and a second transferfield in which the second pattern part is transferred onto the substrateby the second projection optical system are partially overlapped witheach other in a second direction of the substrate. The distance betweenthe center of the first transfer field and the center of the secondtransfer field in the second direction differs from the distance betweenthe center of the first pattern part and the center of the secondpattern part in the first direction.

The projection optical apparatus and the first projection opticalapparatus of the above aspect, using, for example, light beam transfermembers, transfers light beam from two view points or two rows of viewpoints of two projection optical systems or two rows of projectionoptical systems so that the light beams are transferred on a secondobject in opposite directions along a first direction. The secondprojection exposure apparatus of the above aspect includes twoprojection optical systems, each forming a magnified inverted image in ascanning direction, and transfers light beam from two view points of thetwo projection optical systems so that the light beams are transferredon a second object in opposite directions along the scanning direction.As a result, images formed in pattern fields on the first object areprojected by the two projection optical systems or by the two-rows ofprojection optical systems and are formed on the second object in amanner that the images are continuous to one another. This enablesoptimum pattern transfer.

The amount of light beam transferred by a first light beam transfermember and the amount of light beam transferred by a second light beamtransfer member at least overlap each other as viewed in a seconddirection. The amount of light beam transferred from a view point to animage point by the first-row projection optical system and the amount oflight beam transferred from a view point to an image point by thesecond-row projection optical system overlap with each other as viewedin the second direction. This means that the first and second projectionoptical systems are in a nested arrangement and the first-row andsecond-row projection optical systems are in a nested arrangement. Thisarrangement enables miniaturization of the entire projection opticalapparatus, and reduces image oscillation, which may occur when theapparatus is subjected to disturbance such as vibration.

The offset of the position of each pattern field on the first object inthe first direction (scanning direction), which is subjected toprojection performed by the two projection optical systems or the tworows of projection optical systems, and the scanning distance of thesecond object during scanning exposure are optimized in a well-balancedmanner by adjusting the overlap amount etc. of the light beam transferamount etc. The offset may be set to zero as necessary. In this case,the base member of the stage of the first object may be reduced in size.As a result, the pattern is formed with a higher precision. When thescanning distance is shortened, the base member of the stage of thesecond object may be reduced in size. Further, the exposure time isshortened and the exposure throughput is improved.

With the photomask of the above aspect, the first and second projectionoptical systems of the projection optical apparatus of the above aspectenable projection of the image of a pattern of its first row patternpart and its second row pattern part to be projected. Further, thephotomask of the above aspect enables use of the projection opticalapparatus of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an illumination unit and a maskstage of a projection exposure apparatus according to a firstembodiment;

FIG. 2 is a perspective view showing a projection optical apparatusaccording to the first embodiment and its substrate stage;

FIG. 3 is a diagram showing the relationship between viewing fields OF1to OF5 and image fields IF1 to IF5 according to the first embodiment;

FIG. 4 is a diagram showing the structure of projection optical systemsPL1 and PL2 shown in FIG. 2;

FIG. 5(A) is a plan view of a mask MA shown in FIG. 1 and FIG. 5(B) is aplan view of a plate PT shown in FIG. 2;

FIG. 6 is a chart showing the relationship between a mask offset MO andan idling distance RD in the first embodiment;

FIG. 7 is a diagram showing one example of scanning exposure performedat point B2 in FIG. 6;

FIG. 8 is a diagram showing one example of scanning exposure performedin range 3 in FIG. 6;

FIG. 9 is a diagram showing one example of scanning exposure performedat point B4 in FIG. 6;

FIG. 10 is a diagram showing one example of scanning exposure performedin range B1 in FIG. 6;

FIG. 11(A) is a diagram schematically showing exposure performed using aplurality of projection optical systems each having a one-to-oneprojection ratio, FIG. 11(B) is a diagram schematically showing exposureperformed using a plurality of projection optical systems according tothe first embodiment, and FIG. 11(C) schematically shows an exposuremethod that enables a mask to be downsized also in a non-scanningdirection;

FIG. 12 is a diagram showing changes in the positional relationshipbetween the mask MA and the plate PT during scanning exposure in thefirst embodiment;

FIG. 13 is a diagram showing changes in the positional relationshipbetween the mask MA having a predetermined mask offset MO and the platePT during scanning exposure;

FIG. 14 is a diagram showing a projection optical apparatus PLAaccording to a second embodiment of the present invention and also showsthe positional relationship between a mask and a plate;

FIG. 15 is a diagram showing an on-axis projection optical system PLBthat can be used when a mask has the mask offset MO and also shows thepositional relationship between the mask and the plate;

FIG. 16(A) is a plan view of the projection optical system PLB and themask MA shown in FIG. 15, FIG. 16(B) is a plan view of a plate PT shownin FIG. 15, FIG. 16(C) is a diagram showing an off-axis projectionoptical apparatus PLC and a mask, and FIG. 16(D) is a diagram showing aplate exposed using the projection optical apparatus PLC;

FIG. 17 is a diagram showing a projection optical system PL1 accordingto a first modification of the present invention;

FIG. 18(A) is a diagram showing a projection optical system PL1according to a second modification of the present invention, and FIG.18(B) is a plan view showing viewing fields and image fields accordingto the second modification;

FIG. 19(A) is a diagram showing a projection optical system PL1according to a third modification of the present invention, and FIG.19(B) is a plan view showing viewing fields and image fields accordingto the third modification;

FIG. 20 is a perspective view of a mask stage MSTG shown in FIG. 1 onwhich a plurality of masks are mounted according to another embodimentof the present invention;

FIG. 21 is a perspective view showing transfer of mask patterns onto aplate using projection optical systems according to a third embodimentof the present invention;

FIG. 22 is a diagram showing one example method for manufacturing a maskshown in FIG. 21;

FIG. 23 is a perspective view showing transfer of other mask patternsonto a plate using other projection optical systems in the thirdembodiment;

FIG. 24 is a diagram showing one example method for manufacturing a maskshown FIG. 23; and

FIG. 25 is a flowchart showing manufacturing processes for a liquidcrystal display device using the projection exposure apparatus accordingto the embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

A first embodiment of the present invention will now be described withreference to FIGS. 1 to 12.

FIG. 1 shows a schematic structure of an illumination unit and a maskstage of a scanning projection exposure apparatus employing astep-and-scan method in the first embodiment. FIG. 2 shows a schematicstructure of a projection optical apparatus and a substrate stage of theprojection exposure apparatus. In FIGS. 1 and 2, the projection exposureapparatus includes an illumination unit IU, a mask stage MSTG, aprojection optical system PL, a substrate stage PSTG, a drive mechanism(not shown), and a control unit (not shown). The illumination unit IUilluminates a pattern of a mask MA (first object) with illuminationlight emitted from a light source. The mask stage MSTG holds and movesthe mask MA. The projection optical system PL projects a magnified image(an image with an enlargement magnification) of the pattern of the maskMA onto a plate (substrate) PT (second object). The substrate stage PSTGholds and moves the plate PT. The drive mechanism includes, for example,linear motors for driving the mask stage MSTG and the substrate stagePSTG. The control unit centrally controls the operation of the drivemechanism etc. The plate PT of may be, for example, a flat glass platehaving a rectangular shape of 1.9×2.2 m, 2.2×2.4 m, 2.4×2.8 m, or2.8×3.2 m. The plate PT is coated with photoresist (photosensitivematerial) for manufacturing a liquid crystal display device. The surfaceof the plate PT may be, for example, separated in two pattern transferfields EPA and EPB, on each of which a pattern of the mask MA is to betransferred. A ceramic substrate for manufacturing a thin-film magnetichead or a circular semiconductor wafer for manufacturing a semiconductordevice may be used as the plate PT.

In the illumination unit IU shown in FIG. 1, light beams emitted fromthe light source 1, which is for example an ultrahigh-pressure mercurylamp, are reflected by an elliptical mirror 2 and a dichroic mirror 3and then enter a collimating lens 4. A reflection coating of theelliptical mirror 2 and a reflection coating of the dichroic mirror 3selectively reflect light with a certain wavelength range, orspecifically reflect light including g-line (with a wavelength of 436nm), h-line (with a wavelength of 405 nm), and i-line (with a wavelengthof 365 nm). As a result, the light including the g, h, and i-linesenters the collimating lens 4. With the light source 1 arranged at afirst focal position of the elliptical mirror 2, the light including theg, h, and i-lines forms a light source image at a second focal positionof the elliptical mirror 2. Divergent light beams from the light sourceimage are converted to collimated light beams by the collimating lens 4,and the collimated light beams pass through a wavelength selectivefilter 5, which only allows passage of light beams in a predeterminedexposure wavelength range.

The illumination light that has passed through the wavelength selectivefilter 5 passes through a neutral density filter 6, and then isconverged by a converging lens 7 into a light inlet 8 a of a light guidefiber unit 8. The light guide fiber unit 8 may be, for example, a randomguide fiber unit, which is formed by randomly combining a large numberof fibers. The light guide fiber unit 8 has the light inlet 8 a and fivelight outlets 8 b, 8 c, 8 d, 8 e, and 8 f. The illumination light thathas entered through the light inlet 8 a of the light guide fiber unit 8propagates inside the light guide fiber unit 8 and then separatelyemitted from the five light outlets 8 b to 8 f. The light emitted fromthe five light outlets 8 b to 8 f enters five partial illuminationoptical systems IL1, IL2, IL3, IL4, and IL5, each of which partiallyilluminates the mask MA.

The illumination light emitted from each of the light outlets 8 b to 8 fof the light guide fiber unit 8 enters the corresponding one of thepartial illumination optical systems IL1 to IL5, and is collimated by acollimating lens 9 a, which is arranged in the vicinity of each of thelight outlets 8 b to 8 f. The collimated light then enters a fly's eyelens array 9 b, which is an optical integrator. Illumination light froma large number of secondary light sources, which are formed on arear-side focus surface of the fly's eye lens array 9 b of each of thepartial illumination optical systems IL1 to IL5, illuminates a variablefield stop 9 d via a converging lens 9 c. Light beams from the variableviewing field diaphragms 9 d illuminate viewing fields OF1, OF2, OF3,OF4, and OF5 on the mask MA via condenser lenses 9 e in a substantiallyuniform manner. It is an illumination field ILF1 or the like having apredetermined shape defined in each of the viewing fields (fields ofview) OF1 to OF5 by the variable field stop 9 d that is actuallyilluminated. However, the viewing fields OF1 to OF5 having predeterminedshapes will be hereafter described as fields that are illuminated.

Light from the viewing fields OF1 to OF5 formed on the mask MA exposesimage fields IF1, IF2, IF3, IF4, and IF5 formed on the plate PT via thecorresponding first, second, third, fourth, and fifth projection opticalsystems PL1, PL2, PL3, PL4, and PL5 shown in FIG. 2. The projectionoptical systems PL1 to PL5 are telecentric to the side of the mask MAand the side of the plate PT. It is a projection field EF1, which isconjugate to the illumination field ILF1 or the like, defined in each ofthe image fields IF1 to IF5 that is actually exposed. However, the imagefields IF1 to IF5 will hereafter be described as fields that areexposed. In the present embodiment, the five projection optical systems(partial projection optical systems) PL1 to PL5 form the projectionoptical apparatus PL. The projection optical systems PL1 to PL5 formmagnified images of patterns included in the viewing fields OF1 to OF5formed on the mask MA (first plane) onto the image fields IF1 to IF5formed on the surface of the plate PT (second plane) with a commonenlargement magnification M, which is common to all the projectionoptical systems PL1 to PL5.

In the present embodiment, each of the projection optical systems PL1 toPL5 forms an inverted image of a pattern of the mask MA onto the platePT. Accordingly, the enlargement magnification M is smaller than −1. Forexample, the enlargement magnification M may be −2.5 (2.5×). In thepresent embodiment, the surface on which the mask MA is mounted and thesurface on which the plate PT is mounted are parallel to each other.Hereafter, X-axis is defined as extending along a scanning direction SDof the mask MA and the plate PT during scanning exposure within a planeparallel to the mounting surface of the plate PT, Y-axis is defined asextending along a non-scanning direction that is orthogonal to thescanning direction within the plane parallel to the mounting surface ofthe plate PT, and Z-axis is defined as extending along a directionvertical to the mounting surface of the plate PT. In this case, thepattern surface of the mask MA and the surface of the plate PT areparallel to the XY plane. The scanning direction of the mask MA and theplate PT is the direction in the X-axis (X-direction). The non-scanningdirection of the mask MA and the plate PT is the direction in the Y-axis(Y-direction).

In FIG. 1, the mask MA is attracted to and held on the mask stage MSTGby a mask holder (not shown). An X-axis movable mirror 50X and a Y-axismovable mirror 50Y are fixed on the mask stage MSTG. A first laserinterferometer (not shown) is arranged to face the X-axis and Y-axismovable mirrors 50X and 50Y. The first laser interferometer measures theposition of the mask stage MSTG and provides the measurement result to astage drive unit (not shown). In FIG. 2, the plate PT is attracted toand held on the substrate stage PSTG by a substrate holder (not shown).An X-axis movable mirror 51X and a Y-axis movable mirror 51Y are fixedon the substrate stage PSTG. A second laser interferometer (not shown)is arranged to face the X-axis and Y-axis movable mirrors 51X and 51Y.The second laser interferometer measures the position of the substratestage PSTG and provides the measurement result to the stage drive unit(not shown). The stage drive unit controls the position and the movingvelocity of the mask stage MSTG and the substrate stage PSTG based onthe measurement values of the first and second laser interferometers.During scanning exposure, the substrate stage PSTG is driven in theX-direction at velocity M*VM (where M is the enlargement magnificationof the projection optical systems PL1 and PL5) in synchronization withthe mask stage MSTG that is driven in the X-direction at a velocity VM.In the present embodiment, the enlargement magnification M is a negativevalue. Thus, the mask stage MSTG and the substrate stage PSTG arescanned in opposite directions along the X-axis.

The partial illumination optical systems IL1, IL3, and IL5 shown in FIG.1 are arranged at predetermined intervals in the Y-direction(non-scanning direction) to form a first row. In the same manner, theprojection optical systems PL1, PL3, and PL5 in FIG. 2 corresponding tothe partial illumination optical systems IL1, IL3, and IL5 are alsoarranged in the Y-direction to form a first row. The partialillumination optical systems IL2 and IL4 are arranged at predeterminedintervals in the Y-direction to form a second row. The partialillumination optical systems IL2 and IL4 in the second row are shiftedin the (+)X-direction from the first row. The projection optical systemsPL2 and PL4, which correspond to the partial illumination opticalsystems IL2 and IL4, are also arranged at in the Y-direction in the samemanner.

Although not shown, an off-axis alignment unit and an autofocusing unitare arranged in the vicinity of the first-row projection optical systemsand the second-row projection optical systems. The off-axis alignmentunit aligns the plate PT. The autofocusing unit measures the Z-directionpositions of the mask MA and the plate PT (focus positions). In the samemanner, an alignment unit (not shown) for aligning the mask MA is alsoarranged on the mask MA. The alignment units are used to align the maskMA and the plate PT to perform exposure in an overlapped manner on theplate PT. Based on the measurement results of the autofocusing unit, aZ-drive mechanism (not shown) is used to adjust, for example, theZ-direction position of the mask stage MSTG, to focus the imagingsurfaces of the projection optical systems PL1 to PL5 with the surfaceof the plate PT.

The structure and arrangement of the projection optical systems PL1 toPL5 forming the projection optical apparatus PL of the presentembodiment will now be described in detail. The projection opticalsystems PL1, PL3, and PL5 in the first row have the same structure, andthe projection optical systems PL2 and PL4 in the second row have thesame structure. Thus, the structures of the first projection opticalsystem PL1 and the second projection optical system PL2 will be mainlydescribed. FIG. 3 is a plan view showing the relationship between theviewing fields OF1 to OF5 and the image fields IF1 to IF5 that areconjugate to the projection optical systems PL1 to PL5 shown in FIG. 1.FIG. 4 shows the projection optical systems PL1 and PL2 as viewed in theY-direction.

In FIG. 3, a point (view point) that is included in the viewing fieldOF1 of the projection optical system PL1 and is on an optical axis AX11(refer to FIG. 4) of the projection optical system PL1 is defined aspoint a, and a point (view point) that is included in the viewing fieldOF2 of the projection optical system PL2 and is on an optical axis AX21(refer to FIG. 4) of the projection optical system PL2 is defined aspoint b. A point that is included in the image field IF1 of theprojection optical system PL1 on the plate PT and is on an optical axisAX13 (refer to FIG. 4) of the projection optical system PL1 is definedas point A, and a point that is included in the image field IF2 of theprojection optical system PL2 on the plate PT and is on an optical axisAX23 (refer to FIG. 4) of the projection optical system PL2 is definedas point B. The points A and B are conjugate to the points a and b withrespect to the projection optical systems PL1 and PL2. For example, thepoints a and b may be the central points of the viewing fields OF1 andOF2. When, for example, the centers of the illumination fields definedin the viewing fields OF1 and OF2 are not on the optical axes, thepoints a and b may be the centers of the illumination fields or thelike.

The points (including the point a) that are included in the viewingfields OF1, OF3, and OF5 of the projection optical systems PL1, PL3, andPL5 in the first row and are on the optical axes of the projectionoptical systems PL1, PL3, and PL5 are arranged on a straight line C1,which is parallel to the non-scanning direction (Y-direction). Astraight line C2, which links the points (including the point b) thatare included in the viewing fields OF2 and OF4 of the projection opticalsystems PL2 and PL4 in the second row and are on the optical axes of theprojection optical systems PL2 and PL4, is parallel to the straight lineC1, on which the point a is arranged and which is parallel to theY-axis, and is distant from the straight line C1 by a predetermineddistance LM. The distance LM may be regarded as the X-direction (orscanning-direction) distance between the points a and b included in theviewing fields of the projection optical systems PL1 and PL2 (hereaftermay be referred to as the mask inter-field distance LM). The distance LMmay also be regarded as the X-direction distance on the mask MA betweenthe two projection optical systems PL1 and PL2.

The viewing fields OF1, OF3, and OF5 in the first row have the sametrapezoidal shape of which two sides in the Y-direction are the obliquesides of the trapezoid (although the viewing fields OF1 and OF5 arrangedat the two ends each have an inner side parallel to X-axis). The viewingfields OF2 and OF4 in the second row have the trapezoidal shape that isobtained through 180-degree rotation of the viewing field OF3. The shapeof the viewing fields OF1 and OF5 is not limited to the trapezoidalshape. For example, the Y-direction end portions may be formed to betriangular in the Y-direction.

The projection optical systems PL1 to PL5 of the present embodiment eachform an inverted image with the enlargement magnification M. Thus, theimage fields IF1 to IF5 have trapezoidal shapes (180-degree rotated)obtained by magnifying the corresponding viewing fields OF1 to OF5 withthe enlargement magnification M. As a result, the points (including thepoint A) included in the image fields IF1, IF3, and IF5 that are on theoptical axes are arranged on a straight line C3, which is parallel tothe non-scanning direction (Y-direction). A straight line C4, whichlinks the points (including the point B) that are included in the imagefields IF2 and IF4 of the projection optical systems PL2 and PL4 in thesecond row and are on the optical axes of the projection optical systemsPL2 and PL4, is parallel to the straight line C3, on which the point Ais arranged and which is parallel to the Y-axis, and is distant from thestraight line C3 by a predetermined distance LP in the X-direction. Thedistance LP may be the X-direction distance between the points A and Bincluded in the image fields, which are conjugate to the points a and bincluded in the viewing fields of the projection optical systems PL1 andPL2 (hereafter referred to as the plate inter-field distance LP). Thedistance LP may also be referred to as the X-direction distance on theplate PT between the two projection optical systems PL1 and PL2.

In the present embodiment, the optical axes of the projection opticalsystems PL1, PL3, and PL5 in the first row on the mask MA and theoptical axes of the projection optical systems PL1, PL3, and PL5 on theplate PT are shifted from each other by a shift amount (transfer amount)CRK10 in a first deflection direction FD1, which is the +X direction.The optical axes of the projection optical systems PL2 and PL4 in thesecond row on the mask MA and the optical axes of the projection opticalsystems PL2 and PL4 on the plate PT are shifted from each other by ashift amount CRK20 in a second deflection direction FD2, which is the −Xdirection. More specifically, the first deflection direction FD1 and thesecond deflection direction FD2 are face opposite directions along theX-direction.

To shift the optical axes of the projection optical systems on the platePT with respect to the optical axes of the projection optical systems onthe mask MA, that is, to direct light coming from each view point to theconjugate point on the corresponding image field, which is shifted inthe X-direction from each view point, the projection optical system PL1(PL2) includes a first partial optical system SB11 (SB21), a secondpartial optical system SB12 (SB22), and a third partial optical systemSB13 (SB23), which are arranged in the stated order as being nearer tothe mask MA in FIG. 4. The first partial optical system SB11 has theoptical axis AX11 (AX21), which is parallel to the Z-axis. The secondpartial optical system SB12 has the optical axis AX12 (AX22), which isparallel to the X-axis. The third partial optical system SB13 has theoptical axis AX13 (AX23), which is parallel to the Z-axis. The threepartial optical systems SB11, SB12, and SB13 of the first projectionoptical system PL1 and the three partial optical systems SB21, SB22, andSB23 of the second projection optical system PL2 form a one-time imagingoptical system that forms an image (inverted image) of the pattern ofthe mask MA onto the plate PT with the enlargement magnification M.Although the imaging optical system shown in the example of FIG. 4 isseparated in the three partial optical systems SB11, SB12, and SB13, theimaging optical system may have any structure and any arrangement. Theimaging optical system is only required to form an inverted image of thepattern of the mask MA onto the plate PT. For example, an imagingoptical system that forms an even number of intermediate images or acatadioptric system may be employed.

The projection optical system PL1 (PL2) includes a first mirror FM1(FM3) and a second mirror FM2 (FM4). The first mirror FM1 deflects lightbeams from the first partial optical system SB11 (SB21) in the firstdeflection direction FD1 (second deflection direction FD2). The secondmirror FM2 (FM4) deflects light beams from the second partial opticalsystem SB12 (SB22) in the −Z direction. In this case, the mirrors FM1and FM2 of the first projection optical system PL1, which are twodeflection (folding) members (first light beam transfer member),transfer light beams from point a on the mask MA to the conjugate pointA on the plate PT, which is shifted in the first deflection directionFD1 by the shift amount CRK10. The mirrors FM3 and FM4 of the secondprojection optical system PL2, which are two deflection members (secondlight beam transfer member), transfer light beams from the point b onthe mask MA to the conjugate point B on the plate PT, which is at theposition shifted in the second deflection direction FD2 by the shiftamount CRK20.

When the light beams (optical axes) are shifted with the two deflectionmembers, the degree of freedom in arranging the two deflection memberson the optical paths of the projection optical systems PL1 and PL2 issignificantly high. In this case, the projection optical systems PL1 andPL2 are easily formed. Instead of the mirrors, prisms may be used as thedeflection members. Further, instead of using the two deflectionmembers, three or more deflection members may be used to shift the lightbeams. The projection optical systems PL1 and PL2 are arranged atpositions shifted from each other in the Y-direction. The projectionoptical system PL2 may be a 180-degree rotated projection optical systemof the projection optical system PL1. In this case, the shift amountCRK10 and the shift amount CRK20 are the same but are in oppositedirections.

Referring back to FIG. 3, the image fields IF1 to IF5 of the fiveprojection optical systems PL1 to PL5 of the present embodiment arearranged in a manner that the image fields IF1 to IF5 become continuousto one another in the Y-direction when the image fields IF1 to IF5 aremoved relative to one another in the X-direction. However, theprojection optical systems PL1 to PL5 project an image with anenlargement magnification. Thus, the viewing fields OF1 to OF5 of theprojection optical systems PL1 to PL5 have predetermined gapstherebetween in the Y-direction. As shown in FIG. 5(A) and FIG. 1, fiveelongated pattern fields EM10, EM20, EM30, EM40, and EM50 having alength MSL are formed in the pattern formation fields of the mask MA.The pattern fields EM10, EM20, EM30, EM40, and EM50 are arranged atpredetermined intervals in the X-direction. During exposure, the patternfields EM10 to EM50, or specifically the viewing fields OF1 to OF5 ofthe projection optical systems PL1 to PL5, are scanned in a scanningdirection SM1 (in −X direction in the example of FIG. 5(A)). An invertedimage is formed on the plate PT in the present embodiment. Thus, the +Ydirection end portion of the pattern field EM10 (or EM20 or the like) ofthe mask MA and the −Y direction end portion of the pattern field EM20(or EM30 or the like), which is adjacent to the pattern field EM10 havethe same pattern a1 (or a2 or the like) for overlap exposure.

As shown in FIG. 5(B) and FIG. 2, one of the pattern transfer fields onthe plate PT corresponds to the five image fields IF1 to IF5, may beconsidered as five exposure fields EP10, EP20, EP30, EP40, and EP50,with boundary portions of adjacent exposure fields being virtuallyoverlapped. Each exposure field has a length PSL in the X-direction.

FIG. 12 shows the positional relationship between the mask MA and theplate PT during exposure of the pattern of the mask MA in FIG. 5(A) ontothe plate PT shown in FIG. 5(B). As shown in FIG. 12(A), the plate PTmoves in the scanning direction SP1 (+X direction) in synchronizationwith the movement of the mask MA in the scanning direction SM1 (−Xdirection in this example). Then, illumination of the viewing fields OF2and OF4 of the pattern fields EM20 and EM40 is started, and exposure ofthe image fields IF2 and IF4 of the plate PT starts being exposed.Afterwards, the mask MA is moved by the distance LM as shown in FIG.12(B). Then, illumination of the viewing fields OF1, OF3, and OF5 withthe pattern fields EM10, EM30, EM50 is started, and exposure of theimage fields IF1, IF3, and IF5 of the plate PT starts being exposed. Inthis exposure, the image of the pattern fields EM10, EM30, and EM50 andthe image of the pattern fields EM20 and EM40 are exposed at the samepositions in the X-direction in a manner that these images arecontinuous to each other.

As shown in FIGS. 12(C) and 12(D), the plate PT is moved by the distanceLP after the image fields IF2 and IF4 of the plate PT is exposed, andthen the image fields IF1, IF3, and IF5 of the plate PT is exposed. As aresult, inverted images of the patterns of the pattern fields EM10 toEM50 of the mask MA are exposed in the exposure fields EP10 to EP50 ofthe plate PT in a manner that these images are continuous to one anotherin the Y-direction. As shown in FIG. 5(B), the inverted images of thepatterns a1 (or a2 or the like) at two positions on the mask MA overlapeach other in a boundary portion A1 (or A2 or the like) of the adjacenttwo exposure fields EP10 and EP20 (or EP20 and EP30 or the like) on theplate PT. This reduces errors in the continuity of exposed images. Asshown in FIG. 12(D), the scanning on the plate PT needs to be performednot only along the X-direction length PSL (the shortest scanningdistance) of the pattern transfer field EPA on the plate PT but alsoalong the distance LP between the two rows of image fields. The distance(plate inter-field distance) LP may also be referred to as an idlingdistance RD.

After the scanning shown in FIG. 12(D) is performed, the substrate stageis driven to move the plate PT in the +Y direction in a stepwise manner,and then the plate PT is scanned in −X direction using the enlargementmagnification as a velocity ratio in synchronization with the scanningof the viewing fields OF1 to OF5 of the mask MA performed in the +Xdirection. As a result, magnified images of the pattern of the mask MAare exposed in the next pattern transfer field EPB on the plate PT in amanner that the images are continuous to one another.

As described above, the mask MA of the present embodiment shown in FIG.5(A) has the pattern fields EM10 to EM50 arranged at the same positionsin the X-direction. However, when the projection optical systems PL1 toPL5 do not have 1×1 magnification, the relationship between theX-direction distance (mask inter-field distance) LM between the points aand b included in the viewing fields of the projection optical systemsPL1 and PL2 in FIG. 3 and the X-direction distance (plate inter-fielddistance) LP between the points A and B on the plate PT, which areconjugate to the points a and b, must be taken into consideration forexposure of continuous patterns. More specifically, to actually exposethe patterns in the exposure fields EP10 to EP50 onto the plate PT in amanner that the images will be continuous to each other in theY-direction, a predetermined offset MO (hereafter referred to as a maskoffset) MO must be set between the positions of the odd-numbered patternfields EM10, EM30, and EM50, which are illuminated by the first-rowprojection optical systems PL1, PL3, and PL5 shown in FIG. 1, and thepositions of the even-numbered pattern fields EM20 and EM40, which areilluminated by the second-row projection optical systems PL2 and PL4shown in FIG. 1.

FIG. 13 shows the exposure performed on the mask MA having the maskoffset MO. As shown in FIG. 13(A), the distance LP is smaller than thedistance LM. Thus, the mask MA has the predetermined mask offset MO inthe X-direction between the odd-numbered pattern field EM10 or the likeand the even-numbered pattern field EM20 or the like on the mask MA asshown in FIG. 13(C). In this case, the mask MA is scanned in −Xdirection and the viewing fields OF2 and OF4 of the pattern fields EM20and EM40 start being illuminated as shown in FIG. 13(A), and then theplate PT starts being exposed. Afterwards, when the viewing fields OF1,OF3, and OF5 of the pattern fields EM10, EM30, and EM50 starts beingilluminated as shown in FIG. 13(B), an image of the pattern field EM10,EM30, and EM50 and an image of the pattern field EM20 and EM40 areexposed at the same positions on the plate PT in the X-direction.

As shown in FIGS. 13(C) and 13(D), the plate PT moves by the distance LPafter the image field IF2 and IF4 of the plate PT is exposed, and thenthe image field IF1, IF3, and IF5 of the plate PT is exposed. Thiscompletes the scanning exposure of the plate PT. In this case, theidling distance RD (distance LP) of the plate PT is shorter than that inthe scanning exposure shown in FIG. 12. In other words, the mask offsetMO is substantially inversely proportional to the idling distance RD.When the idling distance RD is set lengthened, the mask offset MO isshortened. In this case, the pattern of the mask MA can be downsized inthe scanning direction and the mask stage MSTG can be downsized in thescanning direction. Further, the pattern of the mask MA can be formedwith a higher precision. When the mask offset MO is lengthened, theidling distance RD is shortened. In this case, the base member of thesubstrate stage PSTG can be downsized in the scanning direction, and thetime required for a single scanning exposure can be shortened. In thiscase, the throughput of the exposure process is improved. By balancingthe mask offset MO and the idling distance RD in accordance with theapplication (for example, micropattern or rough pattern) of theprojection exposure apparatus, the cost performance of the projectionexposure apparatus is improved.

In the present embodiment, the mask offset MO and the idling distance RDare well-balanced by setting predetermined conditions between thedistance (mask inter-field distance) LM and the distance (plateinter-field distance) LP.

More specifically, the shift amount CRK10 of the light beams (opticalaxis) of the projection optical system PL1 is a lengthwise element of aline segment a′A (first line segment) in FIG. 4. The line segment a Alinks a point a′, which is obtained by projecting (orthogonallyprojecting) the point a included in the viewing field of the projectionoptical system PL1 onto the plate PT in a manner parallel to Z-axis, andthe point A on the plate PT, which is conjugate to the point a. In thesame manner, the shift amount CRK20 of the light beam (optical axis) ofthe projection optical system PL2 is a lengthwise element of a linesegment b′B (second line segment). The line segment b′B links a pointb′, which is obtained by projecting (orthogonally projecting) the pointb included in the viewing field of the projection optical system PL2onto the plate PT in a manner parallel to Z-axis, and the point B on theplate PT, which is conjugate to the point b.

As one example, the line segment a′A and the line segment b′B at leastpartially overlap each other when viewed in the Y-direction(non-scanning direction) in the present embodiment. When this isassociated with the arrangement of the first-row projection opticalsystems PL1, PL3, and PL5 and the second-row projection optical systemsPL2 and PL4 shown in FIG. 3, the straight line C1 (first row) thatextends on the optical axes of the first-row viewing fields OF1, OF3,and OF5 is between the straight line C2 (second row) and the straightline C4 (fourth row) with respect to the X-direction (scanningdirection) when viewed in the Z-direction. The straight line C2 extendson the optical axes of the second-row viewing fields OF2 and OF4. Thestraight line C4 extends on the optical axes of the viewing fields IF2and IF4 that are conjugate to the viewing fields OF2 and OF4. Thestraight line C2 of the second row is between the straight line C1 ofthe first row and the straight line C3 (third row) with respect to theX-direction (scanning direction). The straight line 3C extends on theoptical axes of the image fields IF1, IF3, and IF5, which are conjugateto the viewing fields arranged along the straight line C1.

Due to such an arrangement, exposure is easily performed in an optimummanner while the exposure fields EP10 and EP20 on the plate PT (or theexposure fields EP10 to EP50) are continuous to one another in theY-direction as shown in FIG. 5(B). Further, the distance LP isrelatively short (the idling distance RD is relatively short), but islonger than the overlapped portions (in other words, the mask offset MOis relatively short). In this case, the mask offset MO and the idlingdistance RD are easily optimized in a well-balanced manner. The maskoffset MO may be set smaller or the idling distance RD may be setshorter when necessary by adjusting the distance LP and the distance LMwithin the range in which the mask offset MO and the idling distance RDare well-balanced.

The line segment a′A and the line segment b′B at least partially overlapeach other as viewed in the Y-direction (or the straight line C1 isbetween the straight lines C2 and C4 and the straight line C2 is betweenthe straight lines C1 and C3). This indicates that the light beams ofthe projection optical system PL1 and the light beams of the projectionoptical system PL2 (or the first-row projection optical systems PL1,PL3, and PL5 and the second-row projection optical systems PL2 and PL4)are transferred in the directions opposite to each other. This alsoindicates that the projection optical system PL1 (or PL1, PL3, and PL5)and the projection optical system PL2 (or PL2 and PL4) partially overlapeach other as viewed in the Y-direction, or in other words, theprojection optical systems PL1 and PL2 (or the projection opticalsystems PL1 to PL5) are in a nested arrangement. This arrangementreduces the entire size of the projection optical apparatus PL, and alsoreduces image oscillation, which may occur when the apparatus issubjected to disturbance such as vibration. As a result, the maskpattern is transferred onto the plate PT with a high precision.

In the present embodiment, the line segment a′A and the line segment b′Bare both parallel to the X-direction. In this case, the projectionoptical systems PL1 and PL2 are simply required to transfer light beamsin the X-direction using light beam transfer members. This simplifiesthe structure of the optical systems.

The relationship between the mask offset MO and the idling distance RDwill now be described in a more precise manner. Referring now to FIG. 4,the X-direction distance (mask inter-field distance) LM between thepoints a and b included in the viewing fields of the projection opticalsystems PL1 and PL2 on the mask MA and the X-direction distance (plateinter-field distance) LP between the points A and B on the plate PT,which are conjugate to the points a and b, and the shift amounts CRK10and CRK20 of the light beams of the projection optical systems PL1 andPL2 have the relationship written as expression (1) below. The distancesLP and LM are assumed to have a positive sign the direction from thepoints B and b to the points A and a is the +X direction. The shiftamounts CRK10 and CRK20 have a positive sign when the direction from thepoints a′ and b′ to the points A and B is the +X direction.

LP=CRK10−CRK20+LM  (1)

In the present embodiment, the distance LP is set within the rangewritten as expression (2) below using the enlargement magnification M(of a negative value) of the projection optical systems PL1 and PL2.

0≦|LP|≦|M*LM|  (2)

The distance LP is a positive value, the distance LM is a negativevalue, and the enlargement magnification M is a negative value in theexample of FIG. 4. In this case, expression (2) may also be written asexpression (2A) below. Expression (2A) will be hereafter used instead ofexpression (2).

0≦LP≦M*LM  (2A)

As shown in FIGS. 5(A) and 5(B), the scanning-direction length MSL ofthe pattern fields EM10 to EM50 of the mask MA (when the mask MA doesnot have the mask offset MO) and the scanning-direction length PSL ofthe exposure fields EP10 to EP50 of the plate PT have the relationshipwritten as expression (3).

PSL=MSL*|M|  (3)

The mask offset MO shown in FIG. 13(C) is written as expression (4)below.

MO=LP/M−LM  (4)

The idling distance RD of the substrate stage PSTG described above isequal to the distance LP, which is written as expression (5) below.

RD=LP  (5)

Expression (4) is transformed into expression (6) below.

RD=M*MO+M*LM  (6)

In the present embodiment, the enlargement magnification M has anegative sign. When the distance LM is a negative value, the idlingdistance RD and the mask offset MO that satisfy expression (6) will havethe relationship shown in FIG. 6. In FIG. 6, the idling distance RD andthe mask offset MO are inversely proportional to each other within therange in which expression (2A) is satisfied (including the point B2, therange B3, and the point B4). In this range, the idling distance RD andthe mask offset MO fall within their predetermined ranges and the idlingdistance RD and the mask offset MO are well-balanced.

At the point B2 at which expression (7) below is satisfied (the upperlimit value of expression (2A)), the mask offset MO is zero and theidling distance RD is the distance LP (=M*LM).

LP=M*LM  (7)

Within the range B1 (LP>M*LM) in which the distance LP exceeds the upperlimit value of expression (2A), the mask offset MO again needs to be setand the idling distance RD increases.

At the point B4 (LP=0) shown in FIG. 6 at which the distance LP is thelower limit value of expression (2A), the idling distance RD is zero butthe mask offset MO is the distance LM (more accurately, −LM). Within therange B5 (LP<0) in which the distance LP exceeds the lower limit valueof expression (2A), the idling distance RD again needs to be set and themask offset MO further increases.

FIG. 7 shows the scanning exposure performed when the distance LPexceeds the upper limit value of expression (2A) (point B2 in FIG. 6).FIG. 8 shows the scanning exposure performed when the distance LP iswithin the range of the conditional expression (range B3 in FIG. 6).FIG. 9 shows the scanning exposure performed when the distance LP is thelower limit value (point B4 in FIG. 6). FIG. 10 shows the scanningexposure performed when the distance LP far exceeds the upper limitvalue (range B1 in FIG. 6). In FIGS. 7 to 10, the mask MA is scanned inthe −X direction and the plate PT is scanned in the +X direction usingthe absolute value of the enlargement magnification M for the projectionoptical systems PL1 and PL2 as the velocity ratio. For the sake ofbrevity, the projection optical system PL1 (pattern field EM10) and theprojection optical system PL2 (pattern field EM20) are switched in theY-direction and the distance LM is expressed as −LM.

FIGS. 7(A), 8(A), 9(A), and 10(A) are plan views showing therelationship between the viewing fields OF1 and OF2 and the image fieldsIF2 and IF2 of the projection optical systems PL1 and PL2. FIGS. 7(B),8(B), 9(B), and 10(B) are plan views showing the state in which thescanning exposure operation is started, or more specifically, the statein which the viewing field OF2 of the mask MA starts being illuminatedand the image field IF2 of the plate PT starts being exposed. In FIG.9(B), the image fields IF1 and IF2 are arranged in the Y-direction. Thissimultaneously starts illumination of the viewing field OF1 with themask MA and exposure of the plate PT with the image field IF1.

FIG. 10(C) shows a state in which the viewing field OF2 of the mask MAhas been completely illuminated and the image field IF2 of the plate PThas been completely exposed. FIGS. 7(C), 8(C), and 10(D) are plan viewsshowing a state in which illumination of the viewing field OF1 of themask MA is started, and exposure of the image field IF1 of the plate PTis started. FIG. 8(D) shows a state in which the viewing field OF2 ofthe mask MA has been completely illuminated and the image field IF2 ofthe plate PT has been completely exposed. FIGS. 7(D), 8(E), 9(B), and10(E) are plan views showing a state in which the scanning exposureoperation has been completed, that is, the viewing field OF1 of the maskMA has been completely illuminated and the image field IF1 of the platePT has been completely exposed.

It is apparent from FIG. 7(D) that the mask offset MO is not generatedbetween the pattern fields EM10 and EM20 of the mask MA when thedistance LP is the upper limit value (M*LM). Thus, the mask stage MSTGcan be downsized. The scanning exposure operation shown in FIGS. 12(A)to 12(D) described above corresponds to the scanning exposure shown inFIG. 7.

As shown in FIG. 8(E), the mask offset MO is generated between thepattern fields EM10 and EM20 of the mask MA when the distance LP iswithin the above range. However, the idling distance RD of the plate PTis short in this case. Thus, the base member of the substrate stage PSTGcan be downsized and the exposure throughput can be improved. It is animperative of the present embodiment that the projection opticalapparatus has an enlargement magnification. Thus, the mask stage MSTGhaving a small pattern does not determine the stage movement velocity.The substrate stage PSTG on which a magnified image is projecteddetermines the stage movement velocity. Accordingly, the shortening ofthe idling distance RD of the substrate stage PSTG will improve theexposure throughput. The scanning exposure operation shown in FIGS.13(A) to 13(D) corresponds to the scanning exposure shown in FIG. 8.

As shown in FIG. 9(C), the mask offset MO is generated between thepattern fields EM10 and EM20 of the mask MA when the distance LP is thelower limit value (or RD=LP=0). However, the idling distance RD of theplate PT can be reduced to zero in this case. The exposure throughput isimproved most effectively in this case.

As shown in FIG. 10(D), the mask offset MO is generated between thepattern fields EM10 and EM20 of the mask MA when the distance LP farexceeds the upper limit value of the conditional expression (orLP>>M*LM). The mask cannot be downsized in this case. The idlingdistance RD of the plate PT is also lengthened, and the exposurethroughput cannot be improved.

The effect of the present embodiment for downsizing the mask will now bedescribed with reference to FIG. 11. FIG. 11(A) shows the positionalrelationship among a mask MA, a plate PT, and seven projection opticalsystems PLA1 to PLA7 included in the conventional multiple projectionoptical system of the equal magnification type. Each of the projectionoptical systems PLE1 to PLE7 shown in FIG. 11(A) has a lateralmagnification of +1 in the scanning direction (X-direction) and alateral magnification of +1 in the non-scanning direction (Y-direction).

FIG. 11(B) shows the positional relationship among the mask MA, theplate PT, and the projection optical systems PL1 to PL5 that are in anested arrangement according to the present embodiment. In thearrangement shown in FIG. 11(B), the mask inter-field distance LM andthe plate inter-field distance LP satisfy LM*M=LP, where M is theenlargement magnification of the projection optical systems PL1 to PL5.In the arrangement shown in FIG. 11(B), the projection optical systemshave an enlargement magnification unlike the projection optical systemsin the arrangement shown in FIG. 11(A). Thus, the arrangement in FIG.11(B) enables the mask pattern to be downsized. This enables the maskstage to be downsized significantly and reduces errors (writing errorsetc.) of the mask pattern. The nested arrangement of the projectionoptical systems PL1 to PL5 in FIG. 11(B) downsizes the entire projectionoptical apparatus as compared with when, for example, the projectionoptical systems PL1 to PL5 are not in the nested arrangement (when theprojection optical systems PL1 and PL2 viewed in the Y-direction do notoverlap each other). Each of the projection optical systems PL1 to PL5in FIG. 11(B) has a negative lateral magnification in the scanningdirection (M<−1) and a negative lateral magnification in thenon-scanning direction (M<−1). Alternatively, each of the projectionoptical systems PL1 to PL5 may have a positive lateral magnification inthe non-scanning direction (M>1). Such a modification of the presentembodiment will be described later.

FIG. 11(C) shows the arrangement in which the viewing fields of theprojection optical systems PL1 to PL5 are arranged more densely in thenon-scanning direction than in the arrangement shown in FIG. 11(B). Morespecifically, in the projection optical systems PL1 to PL5 shown in FIG.11(C) excluding the projection optical system PL3 arranged in themiddle, the central position of the viewing field in the non-scanningdirection and the central position of the viewing field in thenon-scanning direction are shifted from each other. This arrangementenables the mask to be downsized in the non-scanning direction.

Although the projection optical apparatus PL of the present embodimentshown in FIG. 1 includes the five projection optical systems PL1 to PL5,the projection optical apparatus PL is only required to include at leasttwo projection optical systems (partial projection optical systems), forexample the projection optical systems PL1 and PL2.

Second Embodiment

A second embodiment of the present invention will now be described withreference to FIGS. 14 to 20. A stage system of a scanning projectionexposure apparatus according to the second embodiment is similar to thestage system described in the first embodiment. However, a projectionexposure apparatus of the second embodiment differs from the projectionoptical apparatus PL of the first embodiment shown in FIG. 2 in theshift direction and the shift amount of light beams (optical axes) ofeach of its projection optical systems PL1 to PL5. The components shownin FIGS. 14 to 20 corresponding to the components shown in FIGS. 1 to 5are given the same reference numerals and will not be described indetail.

FIGS. 14(A) to 14(C) show a projection optical apparatus PLA of thesecond embodiment. FIG. 14(A) is a plan view showing the arrangement ofa plurality of pattern fields EM10 to EM50 formed on a mask MA. FIG.14(B) is a projection view showing the arrangement of the plurality ofprojection optical systems PL1 to PL5. FIG. 14(C) is a plan view showingthe arrangement of a plurality of exposure fields EP10 to EP50 formed ona plate PT.

The projection optical apparatus PLA shown FIG. 14 differs from theprojection optical apparatus shown in FIG. 3 (first embodiment) in thatthe viewing fields of projection optical systems PL1 to PL5 are arrangeddensely in a direction intersecting with a scanning direction(X-direction). The projection optical apparatus PLA shown in FIG. 14(B)includes the five projection optical systems PL1 to PL5, each of whichincludes first partial optical systems SB11 to SB51, second partialoptical systems (not shown), third partial optical systems SB13 to SB52,and two deflection members (not shown).

The viewing field of the first projection optical system PL1 is alignedwith the pattern field EM10 on the mask MA in a non-scanning direction(Y-direction). Light from the pattern field EM10 is directed in thefirst deflection direction FD1 by a first deflection member (not shown)via the first partial optical system SB11 of the first projectionoptical system PL1 and then passes through the third partial opticalsystem SB13 via the second partial optical system (not shown) and asecond deflection member (not shown). The light that has passed throughthe third partial optical system SB13 reaches part of the exposure fieldEP10 on the plate PT.

In the same manner, the viewing fields of the second to fifth projectionoptical system PL2 to PL5 are respectively aligned with the patternfields EM20 to EM50 in the non-scanning direction. Light from thepattern fields EM20 to EM50 is directed in second to fifth deflectiondirections FD2 to FD5 by the first deflection member (not shown) via thefirst partial optical systems SB21 to SB51 of the second to fifthprojection optical systems PL2 to PL5 and then passes through the thirdpartial optical systems SB23 to SB53 via the second partial opticalsystems (not shown) and the second deflection member (not shown). Thelight that has passed through the third partial optical systems SB23 toSB53 reach parts of the exposure fields EP20 to EP50 on the plate PT.

The third deflection direction FD3 of the third projection opticalsystem PL3, which is in the middle in the non-scanning direction,coincides with the scanning direction. The second and fourth deflectiondirections FD2 and FD4 of the second and fourth projection opticalsystems PL2 and PL4, which are adjacent to the third projection opticalsystem PL3 in the non-scanning direction, are tilted in the non-scanningdirection. The first and fifth deflection directions FD1 and FD5 of thefirst and fifth projection optical systems PL1 and PL5, which areoutward from the second and fourth projection optical systems PL2 andPL4 in the non-scanning direction, are tilted more in the non-scanningdirection than the second and fourth deflection directions FD2 and FD4.

In other words, the third deflection direction FD3 only has a vectorcomponent along the scanning direction. The second and fourth deflectiondirections FD2 and FD4 have vector components along the scanningdirection and the non-scanning direction. The first and fifth deflectiondirections FD1 and FD5 have vector components along the scanningdirection and the non-scanning direction, which are greater than thescanning direction vector components of the second and fourth deflectiondirections FD2 and FD4.

More specifically, the projection optical systems PL1 to PL5 shown inFIG. 14(B) are arranged in the same manner as in the arrangement shownin FIG. 3 (first embodiment) at the side of the plate PT but arearranged more densely in the non-scanning direction at the side of themask MA. This arrangement enables the mask to be downsized also in thedirection intersecting with the scanning direction.

The arrangement of the present embodiment shown in FIG. 14 alsosatisfies the conditional expressions (1) and (2A) described in thefirst embodiment in terms of the X-direction component of the distancebetween the first and second deflection members. In particular, thearrangement shown in FIG. 14(B) satisfies LP=M*LM.

In the arrangement shown in FIG. 14(B), a straight line C1, whichextends through the viewing fields of the first-row projection opticalsystems PL1, PL2, and PL3 on the optical axes of the projection opticalsystems PL1, PL2, and PL3, is arranged between a straight line C2, whichextends through the viewing fields of the second-row projection opticalsystems PL2 and PL4 on the optical axes of the optical systems PL2 andPL4, and a straight line C4, which extends through the image fieldsconjugate to the viewing fields of the projection optical systems PL2and PL4 on the optical axes of the projection optical systems PL2 andPL4. The straight line C2 is arranged between the straight line C1 and astraight line C3, which extends through the image fields conjugate tothe viewing fields arranged along the straight line C1. This nestedarrangement downsizes the projection optical apparatus PLA.

In the above embodiment, the projection optical apparatus is an off-axisprojection optical apparatus that formed by a plurality of off-axisprojection optical systems (PL1 to PL5 etc.), of which viewing fieldsand image fields extend on the optical axes of the projection opticalsystems. Alternatively, the projection optical apparatus may be anon-axis projection optical apparatus that is formed by on-axisprojection optical systems, of which viewing fields and image fields areshifted from the optical axes of the projection optical systems.

For comparison purpose, FIGS. 15(A) to 15(C) show an on-axis projectionoptical apparatus PLB, which can be used when a mask MA has a maskoffset MO as shown in FIGS. 8(A) to 8(E). The projection opticalapparatus PLB shown in FIG. 15(B) includes five on-axis projectionoptical systems PL1 to PL5, of which optical axes extend along thecenters of their viewing fields and image fields. Images of patterns ofpattern fields EM10 to EM50, which are formed on the mask MA having themask offset MO shown in FIG. 15(A), are projected onto exposure fieldsEP10 to EP50, which are formed on a plate PT shown in FIG. 15(C), viathe projection optical systems PL1 to PL5.

FIGS. 16(A) and 16(B) show the same projection optical apparatus PLB asshown in FIGS. 15(A) to 15(C). FIGS. 16(C) and 16(D) show an off-axisprojection optical apparatus PLC that can be used when a mask MA has thesame mask offset MO as the projection optical apparatus PLB. Morespecifically, the projection optical apparatus PLC shown in FIG. 16(A)includes five projection optical systems PL1 to PL5 in which the centersof their viewing fields and image fields are shifted from their opticalaxes in the X-direction. However, the projection optical apparatus PLChas the same function for projecting patterns of the mask MA onto theplate PT as the projection optical apparatus PLB shown in FIG. 16(A).

In the projection optical apparatus PLC shown in FIG. 16(C), the imagefields of the projection optical systems PL1 to PL5 are set to beshifted more toward the corresponding viewing fields in the scanningdirection (X-direction) as compared with the projection opticalapparatus PLB shown in FIG. 16(A) (FIG. 15(B)). In this case, thedistance (plate inter-field distance) LP between the image fields in thescanning direction is shorter than that in the projection opticalapparatus shown in FIG. 16(A). Thus, the projection optical apparatusPLC further shortens the idling distance RD. As a result, the projectionoptical apparatus PLC achieves a higher exposure throughput than theprojection optical apparatus shown in FIG. 16(A).

Although the above embodiments describe a case in which the plurality ofprojection optical systems (PL1 to PL5 etc.) are one-time imagingdioptric systems (optical systems that do not form intermediate images),the projection optical systems is not limited to one-time imagingoptical systems and also not to dioptric systems.

FIG. 17 shows a first projection optical system PL1 according to a firstmodification of the present embodiment. In FIG. 17, in relation with asecond projection optical system adjacent to the projection opticalsystem PL1 in the non-scanning direction (Y-direction), only opticalaxes AX21 and AX23 of the second projection optical system are shown.

The first projection optical system PL1 of the first modification is atwo-time imaging catadioptric system (optical system that forms a singleintermediate image). The first projection optical system PL1 has alateral magnification M with a negative value (M<−1) in the scanningdirection and a lateral magnification M with a positive value (M>1) inthe non-scanning direction. More specifically, the first projectionoptical system PL1 of the first modification forms a magnified invertedimage of a rear surface (magnified inverted mirror image) of part of apattern field formed on a mask MA.

The first projection optical system PL1 shown in FIG. 17 includes afirst imaging optical system for forming an intermediate image IM1 and asecond imaging optical system for imaging the intermediate image IM1again onto the plate PT. The first imaging optical system includes afirst group G11, which is arranged along an optical axis AX11 thatextends in the direction of the normal to the surface of the mask MA, abeam splitter BS, which is either an amplitude splitter or apolarization beam splitter, a second group G12, which includes a concavemirror CM1, and a third group G13, which is arranged along an opticalaxis AX12 that is orthogonal to the optical axis AX11 and extendsparallel to the scanning direction (X-direction). The second imagingoptical system includes a fourth group G14, which is arranged along theoptical axis AX12, an optical path deflecting mirror FL11 for deflectingthe optical axis AX12 to generate an optical axis AX13, and a fifthgroup G15, which is arranged along the optical axis AX13 that isparallel to the optical axis AX11 and extends parallel to the directionof the normal to the plate PT.

A field stop FS1 is arranged at an intermediate image formation positionbetween the first imaging optical system and the second imaging opticalsystem. In the first modification, the field stop FS1 defines theviewing fields on the mask MA and the image fields on the plate PT.Accordingly, when the projection optical systems PL1 and PL2 or the likeaccording to the first modification are used, the illumination unit IUshown in FIG. 1 can eliminate its optical system that includes thevariable diaphragm 9 d and the condenser lens 9 e and defines theillumination field ILF1 and the like. The same applies to othermodifications of the present embodiment, which will be described withreference to FIGS. 18 and 19. The viewing fields and the image fieldsaccording to the first modification shown in FIG. 17 are defined toinclude the optical axes AX11 and AX13 (on-axis viewing fields andon-axis image fields). Alternatively, the viewing fields and the imagefields may be shifted from the optical axes AX11 and AX13. In otherwords, the viewing fields and the image fields may be off-axis viewingfields and off-axis image fields.

In the first modification, the splitting surface of the beam splitter BScorresponds to the first deflection member and the optical pathdeflecting mirror FL11 corresponds to the second deflection member. Thedirection in which the optical axis AX12 linking the beam splitter BSand the optical path deflecting mirror FL11 extends corresponds to thefirst deflection direction.

In the first modification, the X-direction distance LM between the firstprojection optical system PL1 and the second projection optical systemon the mask MA (corresponding to the X-direction distance between theoptical axis AX11 and AX21) and the X-direction distance LP between thefirst projection optical system PL1 and the second projection opticalsystem on the plate PT (corresponding to the X-direction distancebetween the optical axis AX13 and AX23) satisfy LP=M*LM, where M is theenlargement magnification of the projection optical systems. However,this setting can be changed within the range in which 0≦LP≦M*LM issatisfied.

FIG. 18(A) shows a first projection optical system PL1 according to asecond modification as viewed in the Y-direction (non-scanningdirection). FIG. 18(B) is a plan view showing viewing fields and imagefields in the second modification. In FIG. 18(A), in relation with asecond projection optical system adjacent to the first projectionoptical system PL1 in the non-scanning direction (Y-direction), onlyoptical axes AX21 and AX23 of the second projection optical system areshown. Further, FIG. 18(B) only shows the first and second projectionoptical systems PL1 and PL2.

The first projection optical system PL1 according to the secondmodification shown in FIG. 18(A) is a two-time imaging catadioptricsystem (that forms a single intermediate image). The first projectionoptical system PL differs from the first projection optical system ofthe first modification shown in FIG. 17 in its optical path deflectingmirror FL11 for separating the incoming and outgoing optical paths of aconcave reflection mirror with a viewing field separation technique. Thefirst projection optical system PL of the second modification also has alateral magnification being a negative value (M<−1) in the scanningdirection and a lateral magnification M being a positive value (M>1) inthe non-scanning direction. More specifically, the first projectionoptical system PL1 of the second modification forms a magnified invertedimage of a rear surface (magnified inverted mirror image) of a part of apattern field formed on a mask MA.

The first projection optical system PL1 in FIG. 18(A) includes a firstimaging optical system for forming an intermediate image IM1 and asecond imaging optical system for forming the intermediate image IM1again onto the plate PT. The first imaging optical system includes afirst group G11, which is arranged along an optical axis AX11 thatextends in the direction of the normal to the mask MA, a second groupG12, which includes a concave mirror CM1, and a third group G13, whichis arranged along an optical axis AX12 that is orthogonal to the opticalaxis AX1 and extends parallel to the scanning direction (X-direction),and an optical path deflecting mirror FL11, which is arranged on anoptical path between the second group G12 and the third group G13 anddeflects the optical axis AX11 to generate an optical axis AX12. Thesecond imaging optical system includes a fourth group G14, which isarranged along the optical axis AX12, an optical path deflecting mirrorFL12, and a fifth group G15, which is arranged along an optical axisAX13 that is parallel to the optical axis AX11 and extends parallel tothe direction of the normal to the plate PT.

A field stop FS1 is arranged at an intermediate image formation positionbetween the first imaging optical system and the second imaging opticalsystem. In the second modification, the field stop FS1 defines viewingfields on the mask MA and image fields on the plate PT. The viewingfields and the image fields of the second modification are off-axisviewing fields and off-axis image fields that are shifted from theoptical axes AX11 and AX13.

In the second modification, the optical path deflecting mirror FL11corresponds to the first deflection member and the optical pathdeflecting mirror FL12 corresponds to the second deflection member. Thedirection in which the optical axis AX12 linking the optical pathdeflecting mirrors FL11 and FL12 extends corresponds to the firstdeflection direction.

In the second modification, the X-direction distance LM between thecenter of the viewing field OF1 of the first projection optical systemPL1 on the mask MA and the center of the viewing field OF2 of the secondprojection optical system PL2 on the mask MA and the X-directiondistance LP between the center of the image field IF1 of the firstprojection optical system PL1 on the plate PT and the center of theimage field IF2 of the second projection optical system PL2 on the platePT satisfy LP=M*LM, where M is the enlargement magnification of theprojection optical systems PL1 and PL2 as shown in FIG. 18(B). Thisarrangement can be changed within the range in which 0≦LP≦M*LM issatisfied. The conjugate point of the center of the viewing field OF1 ofthe first projection optical system PL1 is the center of the image fieldIF1, and the conjugate point of the center of the viewing field OF2 ofthe second projection optical system PL2 is the center of the imagefield IF2.

FIG. 19(A) shows a first projection optical system PL1 according to athird modification as viewed in the Y-direction (non-scanningdirection). FIG. 19(B) is a plan view showing viewing fields and imagefields in the third modification. The projection optical system PL1 ofthe third modification shown in FIG. 19(A) differs from the projectionoptical system of the second modification shown in FIG. 18 only in thatits optical path deflecting mirror FL11 is arranged to reflect lightbeams in a manner that the reflected light beams cross an optical axisAX11. The other structure of the projection optical system PL1 of thethird modification is the same as the structure of the secondmodification. This particular arrangement of the optical path deflectingmirror FL11 causes a viewing field OF1 and an image field IF1, which arearranged outward from the optical axes AX11 and AX13 in the scanningdirection (X-direction) in the projection optical system PL1 (FIG.18(B)) of the second modification, to be positioned inward from opticalaxes AX11 and AX13 in the third modification. In the same manner, aviewing field OF2 and an image field IF2 of a projection optical systemPL2 are arranged inward from optical axes AX21 and AX23.

In the third modification, the X-direction distance LM between thecenter of the viewing field OF1 of the first projection optical systemPL1 on a mask MA and the center of a viewing field OF2 of the secondprojection optical system PL2 and the X-direction distance LP betweenthe center of the image field IF1 of the first projection optical systemPL1 on a plate PT and the center of an image field IF2 of the secondprojection optical system PL2 satisfy 0≦LP≦M*LM, where M is theenlargement magnification of the projection optical systems PL1 and PL2.In particular, the viewing fields OF1 and OF2 and the image fields IF1and IF2 are arranged inward from the optical axes AX11, AX13, AX21, andAX23 in the scanning direction in the third modification. Thus, thesetting is close to the lower limit value of the above conditionalexpression (0≦LP≦M*LM). This arrangement of the third modificationimproves the exposure throughput as compared with the secondmodification. In the third modification, the conjugate point of thecenter of the viewing field OF1 of the first projection optical systemPL1 is also the center of the image field IF1, and the conjugate pointof the center of the viewing field OF2 of the second projection opticalsystem PL2 is also the center of the image field IF2.

In the above embodiments, the single mask MA, on which the five patternfields EM10 to EM50 are formed, is mounted on the mask stage MSTG asshown in FIG. 1. FIG. 20 shows another modification of the presentembodiment. In the drawing, the components corresponding to thecomponents shown in FIG. 1 are given the same reference numerals. Fivemasks MA1 to MA5 arranged at predetermined intervals in the Y-direction(non-scanning direction) and elongated in the X-axis direction (scanningdirection) may be attracted to and held on the mask stage MSTG by a maskholder (not shown). Patterns of the pattern fields EM10 to EM50 shown inFIG. 1 may be respectively formed on the masks MA1 to MA5.

The mask stage MSTG and the substrate stage PSTG are scanned in theX-direction in synchronization with each other, while the patterns ofthe masks MA1 to MA5 of the modification shown in FIG. 20 are projectedonto the plate PT by the projection optical systems PL1 to PL5 shown inFIG. 2. As a result, the patterns of the masks MA1 to MA5 aretransferred onto the plate PT.

Third Embodiment

A third embodiment of the present invention will now be described withreference to FIGS. 21 to 24. In the third embodiment, a manufacturingmethod for a mask on which patterns are transferred using the projectionoptical apparatus PL of each of the above embodiments (e.g., the mask MAin FIG. 1) will be described.

FIG. 21 is a conceptual diagram describing the positional relationshipbetween patterns of the mask and the patterns transferred onto the platein the embodiment shown in FIGS. 1 and 2. In FIG. 21, a mask MA1includes a pattern field EM10 in a first row and a pattern field EM20 ina second row, which are spaced from each other in a non-scanningdirection (Y-direction). The pattern fields EM10 and EM20 have a lengthin the longitudinal direction that coincides with a scanning direction(X-direction).

The first-row pattern field EM10 includes a first pattern field RP10, ofwhich has a length in the longitudinal direction coinciding with thescanning direction, and a common pattern field RPc, which is adjacent tothe first pattern field RP10 in the non-scanning direction. Thesecond-row pattern field EM20 includes a second pattern field RP20, ofwhich longitudinal direction coincides with the scanning direction, anda common pattern field RPc, which is adjacent to the second patternfield RP20 in the non-scanning direction.

A pattern formed in the first-row pattern field EM10 in FIG. 21 istransferred onto a first exposure field EP20 on a plate PT by the firstprojection optical system PL1. A pattern formed in a second-row patternfield EM20 in FIG. 21 is transferred onto the second exposure field EP20on the plate PT by the second projection optical system PL2. The firstand second exposure fields EP10 and EP20 partially overlap each other inthe non-scanning direction.

The projection optical systems PL1 and PL2 have a negative enlargementmagnification in the scanning direction and a negative enlargementmagnification in the non-scanning direction as described in the aboveembodiments. Thus, the patterns in the first-row first pattern fieldsRP10 and RP20 and the second-row pattern fields EM10 and EM20 areobtained by inverting patterns that are to be transferred using thenon-scanning direction as the axis of symmetry and the scanningdirection as the axis of symmetry. The patterns in the common patternfields RPc of the pattern fields EM10 and EM20 include patterns obtainedby inverting patterns included in the overlapping portion of theexposure fields EP10 and EP20 on the plate PT using the non-scanning asthe axis of symmetry and the scanning direction as the axis of symmetry.

The method for manufacturing the mask MA1 shown in FIG. 21 will now bedescribed with reference to FIGS. 22(A) to 22(D).

FIG. 22(A) is a plan view showing an original pattern OPA correspondingto the pattern to be transferred onto the plate PT shown in FIG. 21. Theoriginal pattern OPA is not be limited to a pattern that is similar tothe pattern transferred to the plate PT and may be, for example, apattern obtained by subjecting the transferred pattern to OPC (opticalproximity correction) for correcting the optical proximity of thepattern.

The original pattern OPA is first separated into a plurality of fieldsPA1, PA2, and PAC using separation lines DL1 and DL2 in accordance withthe size and shape of the image fields of the projection optical systemsPL1 and PL2 that are used. The first field PA1 corresponds to a fieldthat is projected onto the plate PT by solely using the projectionoptical system PL1. The second field PA2 is a field that is projectedonto the plate PT using solely the projection optical system PL2. Thecommon field PAC is a field that is exposed in an overlapped manner ontothe plate PT using both the first and second projection optical systemsPL1 and PL2.

As shown in FIG. 22(B), pattern data including first pattern data PD1and common pattern data PDC is extracted from the original pattern data.The first pattern data PD1 is the original pattern data positionedwithin the first field PA1. The common pattern data PDC is the originalpattern data positioned within the common field PAC. Also, pattern dataincluding second pattern data PD2 and common pattern data PDC isextracted from the original pattern data. The second pattern data PD2 isthe original pattern data positioned within the second field PA2. Thecommon pattern data PDC is the original pattern data positioned withinthe common field PAC.

As shown in FIG. 22(C), the extracted pattern data for the firstprojection optical system PL1 and the extracted pattern data for thesecond projection optical system PL2 are reduced in accordance with theinverse of the enlargement magnification of the first and secondprojection optical systems PL1 and PL2. In the present embodiment, thefirst and second projection optical systems PL1 and PL2 have a negativeenlargement magnification in the scanning direction and have a negativeenlargement magnification in the non-scanning direction. Thus, thereduced pattern data becomes the first inverted pattern data RPD1,second inverted pattern data RPD2, and common inverted pattern data RPDcby inverting the first pattern data PD1, the second pattern data PD2,and the common pattern data PDC using the scanning direction as an axisand the non-scanning direction as an axis.

Based on the first inverted pattern data RPD1, the second invertedpattern data RPD2, and the common inverted pattern data RPDc, a firstpattern field RP10, a second pattern field RP20, and a common patternfield RPc are written using a mask writer to form the first-row patternfield EM10 and the second-row pattern field EM20. FIG. 22(D) is a planview of the mask MA that has been written. FIG. 22(D) is a plan view ofthe mask MA1 viewed from the pattern side of the mask MA1, that is, theprojection optical system side of the mask MA1.

A mask pattern used when the projection optical systems has a negativeenlargement magnification in the scanning direction and a positiveenlargement magnification in the non-scanning direction and amanufacturing method for such a mask pattern will now be described withreference to FIGS. 23 and 24.

A mask MA2 shown in FIG. 23 differs from the mask MA1 shown in FIG. 21in that patterns of its two-row pattern fields EM10 and EM20 of the maskMA2 are obtained by inverting the patterns in the pattern fields EM10and EM20 in FIG. 21 with respect to an axis parallel to the scanningdirection. The manufacturing method for the mask MA2 of FIG. 23 shown inFIGS. 24(A) to 24(D) differs from the manufacturing method for the maskMA1 shown in FIGS. 22(A) to 22(D) in that the first pattern data PD1,the second pattern data PD2, and the common pattern data PDC areinverted with respect the axis that is the non-scanning direction togenerate the first inverted pattern data RPD1, the second invertedpattern data RPD2, and the common inverted pattern data RPDc as shown inFIGS. 24(B) and 24(C). The remaining parts of the manufacturing methodis the same as the manufacturing method shown in FIG. 22 and will not bedescribed.

Although the mask manufacturing method shown in FIGS. 21 to 24 uses thetwo projection optical systems PL1 and PL2, three or more projectionoptical systems may be used. For example, the mask MA including thepattern fields EM10 to EM50 in FIG. 1 can be manufactured using three ormore projection optical systems using the mask data generated in thesame manner as described above.

The mask may have the mask offset MO in the same manner as described inthe above embodiments (e.g., the mask MA shown in FIG. 8). In this case,it is only required that the entire first-row pattern field EM10 and theentire second-row pattern field EM20 in FIG. 22(D) be shifted in thescanning direction by an amount corresponding to the mask offset MO.

The scanning projection exposure apparatus using the projection opticalsystem PL of FIG. 1 in the above embodiment may be used to form apredetermined pattern (e.g., a circuit pattern or an electrode pattern)on a photosensitive substrate (glass plate) to manufacture a microdevicesuch as a liquid crystal display device. A method for manufacturing aliquid crystal display device using the scanning projection exposureapparatus will now be described with reference to a flowchart shown inFIG. 25.

In step S401 (pattern formation process) in FIG. 25, a coating process,an exposure process, and a developing process are preformed. In thecoating process, a photosensitive substrate is prepared by coating asubstrate, on which exposure is to be performed, with photoresist. Inthe exposure process, a pattern of a mask for a liquid crystal displaydevice is transferred and exposed on the photosensitive substrate usingthe scanning projection exposure apparatus. In the developing process,the photosensitive substrate is developed. The coating process, theexposure process, and the developing process constitute a lithographyprocess, through which a predetermined resist pattern is formed on thesubstrate. After the lithography process, an etching process using theresist pattern as a mask, a resist removing process, and other processesare performed. Through these processes, a predetermined patternincluding a large number of electrodes is formed on the substrate. Thelithography and other processes are performed a number of times inaccordance with the number of layers formed on the substrate.

In step S402 (color filter formation process), a color filter is formedby arranging sets of three fine filters corresponding to red (R), green(G), and blue (B) in a matrix, or arranging sets of three striped R, G,and B filters in the horizontal scanning direction. In step S403 (cellassembly process), liquid crystal is injected between the substratehaving a predetermined pattern, which is obtained for example throughstep S401, and the color filter, which is obtained for example throughstep S402. This completes a liquid crystal panel (liquid crystal cell).

In step S404 (module assembly process), other components including anelectric circuit for enabling a display operation of the liquid crystalpanel (liquid crystal cell) and a backlight are mounted on the completedliquid crystal panel (liquid crystal cell). This completes themanufacture of a liquid crystal display device. The manufacturing methodfor the liquid crystal display device described above uses the scanningprojection exposure apparatus of the above embodiments that downsizesmask patterns in the scanning direction. This manufacturing methodenables the mask stage to be downsized and consequently reduces the costfor the mask stage. With this manufacturing method, a liquid crystaldisplay device is manufactured with a high precision. The manufacturingmethod uses the projection exposure apparatus that has a shorter idlingdistance. This manufacturing method enables the substrate stage to bedownsized. With the manufacturing method, a liquid crystal displaydevice is manufactured with a high exposure throughput with low cost.

The present invention should not be limited to the above embodiments butmay be modified variously without departing from the scope and spirit ofthe present invention.

The device manufacturing method of the present embodiment uses theprojection optical apparatus of the present embodiment in its exposureprocess. This enables projected images formed on a second object by aplurality of projection optical systems (in a plurality of rows) to becontinuous from one another in a highly precise manner, and enablessatisfactory pattern transfer. Further, the nested arrangement of theprojection optical systems downsizes the projection optical apparatushaving an enlargement magnification and reduces image oscillation. As aresult, microdevices having large areas are manufactured at a low costwith high precision.

The method of the present embodiment further enables the pattern on thefirst object (mask or the like) to be downsized in the scanningdirection or enables the scanning distance of the second object (plateor the like) to be shortened as necessary. When the pattern on the firstobject is downsized in the scanning direction, the pattern is formedwith high precision and the stage for the first object is downsized.When the scanning distance of the second object is shortened, the basemember for the second object is downsized and the exposure throughput isimproved. As a result, microdevices are manufactured at a low cost aswell as with high precision.

1. A projection optical apparatus for forming a magnified image of afirst object on a second object, wherein the first object is arranged ina first plane, and the second object is arranged in a second planerelatively movable to the magnified image in a predetermined firstdirection, wherein a first view point and a second view point are set inthe first plane, and a first conjugate point and a second conjugatepoint respectively corresponding to the first view point and the secondview point are set in the second plane, the apparatus comprising: afirst projection optical system which directs light beam from the firstview point to the first conjugate point and forming a magnified image ofthe first object in the first plane on the second object in the secondplane; and a second projection optical system which directs light beamfrom the second view point to the second conjugate point and forming amagnified image of the first object in the first plane on the secondobject in the second plane; wherein the first projection optical systemincludes a first light beam transfer member which transfers the lightbeam from the first view point to the first conjugate point by shiftingthe light beam in the first direction from the first view point; andwherein the second projection optical system includes a second lightbeam transfer member which transfers the light beam from the second viewpoint to the second conjugate point by shifting the light beam in thefirst direction from the second view point.
 2. The projection opticalapparatus according to claim 1, wherein when the second plane is aprojection plane, a first line segment linking a first projected point,which orthogonally projects the first view point, and the firstconjugate point and a second line segment linking a second projectedpoint, which orthogonally projects the second view point, and the firstline segment and second line segment overlap each other within thesecond plane as viewed in a second direction that is orthogonal to thefirst direction.
 3. The projection optical apparatus according to claim2, wherein at least one of the first line segment and the second linesegment is parallel to the first direction.
 4. The projection opticalapparatus according to claim 2, wherein at least one of the first linesegment and the second line segment is non-parallel to the firstdirection and the second direction.
 5. The projection optical apparatusaccording to claim 1, wherein: the first light beam transfer membertransfers the light beam from the first view point in a first deflectiondirection that is parallel to the first line segment; and the secondlight beam transfer member transfers the light beam from the second viewpoint in a second deflection direction that is parallel to the secondline segment.
 6. The projection optical apparatus according to claim 5,wherein: the first light beam transfer member includes a firstdeflection member which deflects the light beam from the first viewpoint in the first deflection direction and a second deflection memberwhich deflects the light beam traveling in the first deflectiondirection toward the second plane; and the second light beam transfermember includes a third deflection member which deflects the light beamfrom the second view point in the second deflection direction and afourth deflection member which deflects the light beam traveling in thesecond deflection direction toward the second plane.
 7. The projectionoptical system according to claim 6, wherein: the first projectionoptical system includes a first partial optical system arranged on anoptical path between the first plane and the first deflection member, asecond partial optical system arranged on an optical path between thefirst deflection member and the second deflection member, and a thirdpartial optical system arranged on an optical path between the seconddeflection member and the second plane; and the second projectionoptical system includes a fourth partial optical system arranged on anoptical path between the first plane and the third deflection member, afifth partial optical system arranged on an optical path between thethird deflection member and the fourth deflection member, and a sixthpartial optical system arranged on an optical path between the fourthdeflection member and the second plane.
 8. The projection optical systemaccording to claim 5, wherein: when M represents enlargementmagnification of the first and second projection optical system, LMrepresents distance between the first view point and the second viewpoint in the first direction, and LP represents distance between thefirst conjugate point and the second conjugate point in the firstdirection, 0≦|LP|≦|M*LM| is satisfied.
 9. The projection opticalapparatus according to claim 8, wherein: the enlargement magnification Mand the distances LM and LP satisfy the equation of LP=M*LM.
 10. Theprojection optical apparatus according to claim 1, wherein: the firstplane includes first and second pattern fields, in which patternsprojected onto the second object in the second plane by the first andsecond projection optical systems, the first and second pattern fieldsbeing arranged at a predetermined interval in a second direction that isorthogonal to the first direction and at the same position in the firstdirection; and the second plane includes first and second exposurefields, onto which an image of the pattern is projected by the first andsecond projection optical systems, wherein the first and second exposurefields contact or partially overlap each other in the second directionat the same position in the first direction.
 11. The projection opticalapparatus according to claim 1, wherein the first and second projectionoptical systems are image-side telecentric optical systems.
 12. Theprojection optical apparatus according to claim 1, further comprising: athird projection optical system which directs light beam from a thirdview point on the first plane to a third conjugate point on the secondplane corresponding to the third view point and forming a magnifiedimage of the first object in the first plane on the second object in thesecond plane; and a fourth projection optical system which directs lightbeam from a fourth view point on the first plane to a fourth conjugatepoint on the second plane corresponding to the fourth view point andforming a magnified image of the first object in the first plane on thesecond object in the second plane; wherein the third projection opticalsystem includes a third light beam transfer member which transfers thelight beam from the third view point to the third conjugate point byshifting the light beam from the third view point in a directionintersecting the first direction; and wherein the fourth projectionoptical system includes a fourth light beam transfer member whichtransfers the light beam from the fourth view point to the fourthconjugate point by shifting the light beam from the fourth view point ina direction intersecting the first direction.
 13. The projection opticalapparatus according to claim 12, wherein the third and fourth projectionoptical systems are arranged outward from the first and secondprojection optical systems.
 14. A projection optical apparatus forforming a magnified image of a first object on a second object, whereinthe first object is arranged in a first plane, and the second object isarranged in a second plane spaced from the first plane, relativelymovable to the magnified image in a predetermined first direction, theapparatus comprising: a first-row projection optical system including aplurality of projection optical systems, each including a viewing fieldon a first row extending along a second direction that intersects thescanning direction; and a second-row projection optical system includinga plurality of projection optical systems, each including a viewingfield on a second row extending along the second direction and differingfrom the first row; wherein the first-row projection optical systemforms, on the second plane, a plurality of image fields conjugate to theplurality of viewing fields of the first-row projection optical systemalong a third row; wherein the second-row projection optical systemforms, on the second plane, a plurality of image fields conjugate to theplurality of viewing fields of the second-row projection optical systemalong a fourth row; and wherein the first row is between the second rowand the fourth row and the second row is between the first row and thethird row when the first to fourth rows are viewed in a directionlinking the first plane and the second plane.
 15. A projection exposureapparatus for exposing a second object with illumination light via afirst object, the apparatus comprising: an illumination optical systemwhich illuminates the first object with the illumination light; theprojection optical apparatus according to claim 1 which forms an imageof the first object illuminated by the illumination optical system onthe second object; and a stage mechanism which relatively moves thefirst object and the second object in the first direction usingenlargement magnification of the projection optical apparatus as avelocity ratio.
 16. A projection exposure apparatus for exposing a firstobject arranged in a first plane and a second object arranged in asecond plane while relatively moving the first object and the secondobject in a predetermined scanning direction, wherein the first planeincludes a first viewing field and a second viewing field, and thesecond plane includes a first projection field and a second projectionfield, the apparatus comprising: a first projection optical system whichprojects a magnified image of part of the first object in the firstviewing field onto the first projection field of the second plane; asecond projection optical system which projects a further magnifiedimage of part of the first object in the second viewing field onto thesecond projection field of the second plane; and a stage mechanism whichrelatively moves the first object and the second object in the scanningdirection using enlargement magnification related with the scanningdirection as a velocity ratio; wherein the enlargement magnification ofthe first projection optical system and the second projection opticalsystem related with the scanning direction is less than −1.
 17. Theprojection exposure apparatus according to claim 16, further comprising:a first-row projection optical system including a plurality ofprojection optical systems, each including a viewing field on a firstrow extending along a non-scanning direction that intersects thescanning direction; and a second-row projection optical system includinga plurality of projection optical systems, each including a viewingfield on a second row extending along the non-scanning direction anddiffering from the first row; wherein the first-row projection opticalsystem forms on a third row a plurality of imaging fields conjugate tothe plurality of viewing fields of the first-row projection opticalsystem; wherein the second-row projection optical system forms on afourth row a plurality of imaging fields conjugate to the plurality ofviewing fields of the second-row projection optical system; wherein thefirst row is between the second row and the fourth row and the secondrow is between the first row and the third row when the first to fourthrows are viewed in a direction linking the first plane and the secondplane; wherein the plurality of projection optical systems of thefirst-row projection optical system include the first projection opticalsystem; and wherein the plurality of projection optical systems of thesecond-row projection optical system include the second projectionoptical system.
 18. The projection exposure apparatus according to claim16, wherein the stage mechanism includes a mask stage which holds amask, wherein the mask includes patterns respectively projected onto thesecond object in the second plane by the first and second projectionoptical systems and includes integrally formed first and second patternfields.
 19. The projection exposure apparatus according to claim 16,wherein the stage mechanism includes a mask stage which holds a firstmask and a second mask, with the first mask including a first patternfield containing a pattern projected onto the second plane by the firstprojection optical system is formed, and the second mask including asecond pattern field containing a pattern projected onto the secondplane by the second projection optical system.
 20. An exposure methodfor exposing a second object with illumination light via a first object,the method comprising: illuminating the first object with theillumination light; projecting an image of the illuminated first objectonto the second object with the projection optical apparatus accordingto claim 1; and relatively moving the first object and the second objectusing the enlargement magnification of the projection optical apparatusas a velocity ratio.
 21. A device manufacturing method comprising:exposing a mask pattern onto a photosensitive substrate using theprojection exposure apparatus according to claim 15; and developing thephotosensitive substrate that has been exposed in the exposing.
 22. Aphotomask for transferring a pattern onto a predetermined substrate, thephotomask comprising: a first-row pattern part and a second-row patternpart spaced from each other in a first direction on the photomask;wherein the first-row pattern part includes a first inverted patternobtained by inverting a pattern in a first original pattern field, whichis part of an original pattern corresponding to the pattern transferredonto the predetermined substrate, using the first direction as an axisof symmetry; the second-row pattern part includes a second invertedpattern obtained by inverting a pattern in a second original patternfield, which differs from the first original pattern field, using thefirst direction as an axis of symmetry; and the first-row pattern partand the second-row pattern part include a common inverted patternobtained by inverting an original pattern in a common field between thefirst original pattern field and the second original pattern field usingthe first direction as an axis of symmetry.
 23. The photomask accordingto claim 22, wherein: the photomask is used to transfer a pattern onto apredetermined substrate with a plurality of spaced projection opticalsystems; the first-row pattern part is transferred onto thepredetermined substrate by a first projection optical system of theplurality of projection optical systems; the second-row pattern part istransferred onto the predetermined substrate by a second projectionoptical system of the plurality of projection optical systems, thesecond projection optical system differing from the first projectionoptical system; and the common inverted pattern of the first-row patternpart and the common inverted pattern of the second-row pattern partoverlap each other on the predetermined substrate.
 24. The photomaskaccording to claim 23, wherein the first-row pattern part and thesecond-row pattern part are spaced from each other in accordance withthe distance between the first and second projection optical systems inthe first direction.
 25. The photomask according to claims 22, whereinthe common inverted pattern is arranged in a field of the first-rowpattern part that is opposite to the second-row pattern part and a fieldof the second-row pattern part that is opposite to the first-row patternpart.
 26. The photomask according to claims 22, wherein the commoninverted pattern is arranged in a field of the first-row pattern part ata side of the second-row pattern part and in a field of the second-rowpattern part at a side of the first-row pattern part.
 27. The photomaskaccording to claim 22, wherein the entire first-row pattern part isshifted from the entire second-row pattern part in a second directionthat is orthogonal to the first direction.
 28. A method formanufacturing the photomask according to claim 22, the methodcomprising: preparing the original pattern; extracting first patterndata, which is data of the original pattern in the first originalpattern field that is part of the original pattern, second pattern data,which is data of the original pattern in the second original patternfield that differs from the first original pattern field, and commonpattern data, which is data of the original pattern in a common patternfield between the first and second pattern fields; inverting the firstpattern data, the second pattern data, and the common pattern data usingthe first direction as an axis of symmetry to obtain first invertedpattern data, second inverted pattern data, and common inverted patterndata; and writing the first inverted pattern data and the commoninverted pattern data to a first field on the photomask and writing thesecond inverted pattern data and the common inverted pattern data to asecond field on the photomask to form the first-row pattern part and thesecond-row pattern part.
 29. A photomask for transferring a pattern ontoa predetermined substrate with first and second projection opticalsystems including a predetermined projection magnitude, the photomaskcomprising: a first pattern part and a second pattern part spaced fromeach other in a first direction on the photomask; wherein a firsttransfer field in which the first pattern part is transferred onto thesubstrate by the first projection optical system and a second transferfield in which the second pattern part is transferred onto the substrateby the second projection optical system are partially overlapped witheach other in a second direction of the substrate; and the distancebetween the center of the first transfer field and the center of thesecond transfer field in the second direction differs from the distancebetween the center of the first pattern part and the center of thesecond pattern part in the first direction.
 30. The photomask accordingto claim 29, wherein the distance between the center of the firsttransfer field and the center of the second transfer field in the seconddirection is shorter than the distance between the center of the firstpattern part and the center of the second pattern part in the firstdirection.
 31. The photomask according to claim 30, wherein the firstdirection and the second direction are parallel to each other.